What kind of house? Primary residence for both of you? Only one of you? If so, which one? Maybe it's rental property the two of you own together? Are you both on the mortgage? Are you both on the deed? We really need more information. Otherwise, the answers provided are only based on assumptions, and our assumptions are usually wrong.
Private house. We both live in the house. We are both on the mortgage but my mother does most of the paying.
Maybe. If more than one taxpayer owns the home and pays mortgage interest (other than a married couple filing a joint return), each may deduct the interest paid if legally liable for the mortgage. If the bank issues Form 1098 with two or more homeowners' names on the form, each homeowner may only deduct the mortgage interest (and real estate taxes) paid using their funds.
If each person paid 50% of the mortgage, each person is only eligible to deduct 50% of the interest. However, if one person made 100% of the payments, they could claim 100% of the mortgage interest deduction.
If one of the homeowners cannot/does not Itemize deductions, the homeowner who does itemize cannot deduct the full amount of the interest shown on the Form 1098 unless he or she paid the interest.
If both of you pay mortgage interest, but the Form 1098 shows only one name as the payer of record on the mortgage, that taxpayer may deduct only that portion of the interest which he or she paid. The taxpayer also should let the other borrower(s) know the amount of interest he (or they) paid.
Deducting Mortgage Interest FAQs https://turbotax.intuit.com/tax-tips/home-ownership/deducting-mortgage-interest-faqs/L4a9KF9mI